Radio Base Station for Combined Radio Communication

ABSTRACT

Radio base station, having a first radio module for radio communication with first radio communication devices, and a connection for connecting an ESL radio module for radio communication with electronic display panels, wherein the radio base station has a first, in particular software-based, control stage for controlling the radio communication of the first radio module according to a first communication protocol, and a second, in particular software-based, control stage for controlling the radio communication of the ESL radio module connectable to the connection according to a second communication protocol, and a, in particular software-based, third control stage for predictively changing a time sequence, defined for a future period, of radio activities of the first radio module on the basis of radio activities of the ESL radio module that are defined for said future period.

TECHNICAL FIELD

The invention relates to a radio base station for combined radiocommunication.

The invention further relates to a system with said radio base station.

Background

A radio base station (also called radio access point or simply accesspoint) mentioned in the beginning for combined WLAN and ESLcommunication is known for example from the WO 2016/045707. The knownradio base station comprises both a separate WLAN radio module for WLANcommunication and a separate ESL radio module for ESL communication. Thetwo radio modules are connected to a control line. With the aid of thecontrol line the one radio module can influence the radio activity ofthe other radio module in order to process its radio activities withoutinterference.

The mutual interaction with the aid of the control line providesbasically a very robust solution. However, it means that the radio basestation has to be adapted at relatively great expense in terms ofhardware.

It is the objective of the invention to propose an improved radio basestation.

SUMMARY OF THE INVENTION

This objective is met by a radio base station according to claim 1.Accordingly the subject of the invention is a radio base stationcomprising a first radio module for radio communication with first radiocommunication devices and a connection for connecting an ESL radiomodule for radio communication with electronic display signs, whereinthe radio base station comprises a first, in particular software-based,control stage for controlling the radio communication of the first radiomodule according to a first communication protocol, and a second, inparticular software-based, control stage for controlling the radiocommunication of the ESL radio module connectable to the connectionaccording to a second communication protocol, and a, in particularsoftware-based, third control stage for predictively changing a timesequence defined for a future time period of radio activities of thefirst radio module, on the basis of radio activities defined for saidfuture time period, of the ESL radio module.

The objective is further met by a system according to claim 10. Thesubject of the invention is therefore also a system comprising aninventive radio base station and an ESL radio module connected to theconnection.

The object is further met by a method according to claim 12. Accordinglythe subject of the invention is a method for controlling a radiocommunication of a radio base station, wherein the radio base stationcomprises a first radio module for radio communication with first radiocommunication devices and a connection for connecting an ESL radiomodule for radio communication with electronic display signs, whereinaccording to the method a first, in particular software-based, controlstage controls the radio communication of the first radio moduleaccording to a first communication protocol, and a second, in particularsoftware-based, control stage controls the radio communication of theESL radio module connected to the connection according to a secondcommunication protocol, and a third, in particular software-based,control stage predictively changes a time sequence defined for a futuretime period of radio activities of the first radio module on the basisof radio activities of the ESL radio module as defined for said futuretime period.

The measures according to the invention bring with them the advantagethat the radio activity of the first radio module can be activated andmuted not only for a defined time period concerning a radio activity tobe currently performed, but that decisions can be taken as regards theavailability of the respective radio activities for a future time periodacross a time sequence of planned radio activities. This corresponds toplanning/coordination of the time ranges available to the first radiomodule within the future time period, in order to accommodate the radioactivities of the first radio module within the future time period in aselection of free time ranges. The time ranges predictively occupied orprobably to be occupied by the ESL radio module for said time period areomitted for the radio activities of the first radio module, so that thefuture radio activities of the ESL radio module can run withoutinterference within the future time period. A future time periodgenerally extends following the currently running radio activity, inparticular in relation to the currently running radio activity of theESL radio module, wherein it covers, viewed over time, a number ofseveral radio activities.

Further, in particular advantageous, designs and further developments ofthe invention are revealed in the dependent claims and the subsequentdescription. Features of one claim category can be further developedcorresponding to features of the other claim category, so that theeffects and advantages stated in conjunction with the one claim categoryalso exist for the other claim category.

Radio activities are understood to be both transmitting and receivingradio activities.

The first radio model can basically support any random radio standarddiffering from the ESL radio module. For example ZigBee or BlueTooth maybe used. However the particularly preferred use of the invention lies ina configuration of the radio base station, in which the first radiomodule is WLAN capable—WLAN meaning “wireless local area network”- orWi-Fi certified (e.g. IEEE-802.11). The same applies to the first radiocommunication devices. Such a first radio module produces a hardlypredictable radio traffic, the influence of which on time-critical radioactivities of the ESL radio module can be serious, unless the measuresspecified in the invention are taken.

The ESL radio module is a radio module developed for communicating withelectronic display signs, in particular price or product informationdisplay signs. The technical jargon for such electronic display signs is“electronic shelf label” or ESL for short.

The connection may be any connection designed for parallel or serialdata transmission. The design of the connection may refer to bothelectro-mechanical connections as well as, as required, to electronic(switching) components or protocol aspects. Furthermore the connectionmay be designed according to the specification of a standardisingorganisation or a consortium. For example the connection may be aproprietary plug, which is used for Ethernet communication. It may alsobe a known “universal serial bus” connection, which may be present inthe different variants (USB 1, 2, 3) or constructional designs (e.g.micro, mini etc. or also type C). The ESL radio module may be connectedto the USB connection outside the device housing of the radio basestation or accommodated within the device housing. In particular then,when both radio modules are accommodated in a single device housing,both aerials (at least two) of the two radio modules are attachedrelatively closely to each other on the device housing. This may howeveralso be case with an ESL radio module located outside the device housingof the radio base station.

The above-mentioned electronic display signs may, for their energysupply, have an energy store such as a battery or a solar panel coupledto a rechargeable battery (e.g. accumulator). A display unit of suchdisplay signs may for example be realised with the aid of LCDtechnology, preferably however electronic ink technology (also callede-ink as synonym for electronic paper).

In order to operate as energy-efficiently as possible, the display signshave various operating states. When in an active state, the energyconsumption of a display sign is relatively high. The active stateexists e.g. during transmitting radio activities for the transmission ofdata and during receiving radio activities for the receipt of data,during internal processing of data such as during updating the contentsof the display (the so-called display update) or when taking batteryvoltage measurements. In the sleep state by contrast the energyconsumption is relatively low. For the sleep state as many electroniccomponents as possible are preferably isolated/disconnected from theenergy supply or at least operated in a mode with minimum energy demand.

Consequently the active state predominantly exists in the time rangesdefined for when the display sign communicates with the ESL radiomodule. In the active state the display sign comprises ready-to-receivecapability in order to receive commands and, as required, also toreceive data from the ESL radio module and process it with the aid ofits logic level. In the active state it is also possible with the aid ofthe logic level to generate transmission data and communicate it to theESL radio module. In order to work in an energy-efficient manner andthereby to achieve as long a service life as possible for the battery ofthe display sign, the basic operating strategy consists in keeping thedisplay sign in the sleep state for as long as possible and only operateit in the active state for a shortest possible time range, when this isabsolutely necessary for the purpose of data transmission to the ESLradio module or for ascertaining synchronism.

With such display signs relatively high energy consumption is alwaysinevitable in case of a communication with the ESL radio module.Therefore disturbances in this radio activity caused by another, i.e.the first radio module, which of necessity lead to an undesirablelengthening of the communication duration of the respective display signwith the associated ESL radio module, have an extremely negative effecton the service life of the battery of the electronic display sign. Forthe first time now, the invention makes it possible, within a definedfuture time period, to give predictive preference to the ESL radiomodule used for the communication with the electronic display signs andthereby to predictively avoid disturbances in radio traffic with theelectronic display signs.

The inventive measures therefore, expressed in other words, ensure thatfuture use of the common radio medium can be planned/coordinated,wherein care must be taken that always only mutually compatible radioactivities of the two radio modules are present, which do not lead toany mutual negative interference. Such joint simultaneous utilisation ofthe radio medium is e.g. given then, when both radio modules showsimultaneous receiving radio activity, but on different radio channels.Apart from this special case it will typically always be the case thatin planning its future use the radio medium is used exclusively by theone or the other radio module. The reason, why this is important, isbecause the two radio aerials of the two radio modules are positioned inrelatively close proximity to each other, so that mutual negativeinterference has always to be expected if both radio modulessimultaneously show radio activities, independently of whether the tworadio modules use different radio channels.

Said coordination is preferred of necessity if both radio communicationsare taking place in the same frequency band, e.g. in the 2.4 GHzfrequency band. Typically different channels can be used in a frequencyband (2.4 GHz defines a total of 79 channels, therefore it is possibleto have several channels on different frequencies; different systems mayhave different channel widths—WLAN has a channel width of 20 MHz, theESL radio system has only 1 MHz channel width).

Now, in the simplest case, it would be possible to use differentchannels with non-overlapping frequencies for the first radio module andthe ESL radio module, and there would in theory be no mutualinterference between the two systems. In reality however no transceiveris perfect and interference signals will always be generated duringtransmission outside the chosen frequency of the channel. Thusinterferences occur on lower or higher frequencies, which diminish asthe distance between frequencies increases (sideband interferences). Inthe main the interference signal interferes during receipt of data(=receiving radio activity), because the data arrives at the radio basestation with very low power. Power decreases quadratically withdistance. Signals transmitted by the radio base station itself arehardly affected because these with their strong transmission poweroutshine the sideband interference of the other radio module. Thiseffect is called “blocking”. It would be possible, with very expensivehardware filters to strongly reduce the interference signal on thesidebands, but on grounds of cost this is not done in practice.

In particular then, when channels on the same frequency/on overlappingfrequencies are used for the first radio module and the ESL radiomodule, it is mandatory that transmitting radio activities of the ESLradio module (e.g. for sending the synchronisation data signal or alsodata packets) are protected against signal interferences caused by thefirst radio module. In practice however, this case can be avoidedthrough a suitable choice of channel without overlapping frequencies,which contributes to improved performance of the overall system, becausetemporal transmission restrictions are reduced or completely avoided.

Now, if channels are used for both radio modules, which show nooverlapping frequencies, the focus during predictiveplanning/coordination is less on the signals (transmitting radioactivity) sent by the base station (in particular the ESL radio module),but above all on those signals transmitted by ESL itself, which areexpected from the ESL radio module during fixed predefined time windows.This may be for example acknowledgement data or partial acknowledgementdata, which is generated by ESL in consequence of the execution ofcommands previously received by the ESL radio module. It is evenpossible for transmitting radio activities of the first radio module tooccur at the same time as these ESL-radio-module-receiving radioactivities.

It is however worth recommending when using different channels withoutoverlapping frequencies, that also those situations be treatedpredictively, in which transmitting by the first radio module andreceiving by the ESL radio module or vice versa occurs simultaneously.

According to a preferred aspect of the invention a second communicationprotocol different from the first communication protocol is used duringcommunication with the electronic display signs. In particular this is aproprietary time slot communication process or protocol, in which, inrepeating sequence, a number of time slots per time slot cycle areavailable for communication, wherein in particular each time slot ischaracterised by a unique time slot symbol. As part of this time slotcommunication process individual electronic display signs can beaddressed and/or provided with (command/display) data, and also data canbe received from the display signs.

With the time slot communication process m time slots, e.g. 256 timeslots are used within e.g. n seconds, such as 15 seconds. The n secondsform a time slot cycle, which continuously repeats. In this time slotcommunication process m time slots are thus available within one timeslot cycle for a communication with the display signs. Each of thesedisplay signs may be assigned to one of the time slots, wherein evenseveral electronic display signs may be assigned to one certain timeslot. In a system, in which e.g. during a time slot cycle of 15 secondsthere exist 256 time slots of 58.5 milliseconds each, it is possible toaddress two to five display signs per time slot individually withoutproblems and to delegate individual tasks with a command to them. Eachelectronic display sign can confirm execution (completion) of anexecuted command with acknowledgement data, which is preferably sent inthat time slot, in which the command was received. Outside the time slotdefined for the respective electronic display sign the electronicdisplay sign is predominantly operated in the energy-saving sleep state.

In order to ensure synchronism in the ESL radio system (ESL radio moduleand a number of radio-technically assigned electronic display signs),the ESL radio module is configured to send a synchronisation data signalcomprising the time slot symbol for the currently present time slot,preferably at the beginning of each time slot.

In the sleep state the logic level/a temporal control stage of theelectronic display sign performs only those activities, which are neededfor correctly timing the waking-up, so that the price display sign candetermine its synchronous state (synchronism with the ESL radio module)at the next time slot destined for it for receiving the synchronisationdata signal, and/or is ready for communication with the radio module.Each display sign knows, which time slot symbol indicates the time slotdestined for it. Each display sign thus orientates itself individuallyon the occurrence of a time slot symbol relevant to it, identifies thetime slot symbol relevant to it and defines its next waking-up timeusing the timing of the time slot communication process predefined bythe radio base station. The display sign thus determines its synchronismwith the ESL radio module solely through recognising the time slotsymbol, which occurs at the expected point of time/appears in anexpected time window and which indicates the time slot destined for it.Such a time slot symbol may for example be given by the lowest-valuebyte of the individual and unique device address of the display sign.Insofar as no individual addressing exists for the display signdetermining its synchronism, this will immediately after recognising itssynchronism change back into the energy-saving sleep state and remain inthis sleep state until the next waking-up time. A synchronous displaysign will thus be operated for as long as possible in its sleep statewith the lowest possible energy consumption, in order to extend theservice life of the battery for as long as possible. In case synchronismis not detected because for example the radio activity of the ESL radiomodule was disturbed, the electronic display sign would assume a stateof increased energy consumption in order to bring about an automatic, inparticular autonomous re-synchronisation (i.e. without bi-directionalcommunication with the radio base station).

Since, as revealed in the preceding discussions, the secondcommunication protocol preferably used with the ESL radio modulerequires a very strict temporal behaviour of the radio activities or atleast of some of the radio activities such as the emitting of a timeslot symbol, it has proven to be particularly efficient tosystematically exclude the interferences, which can occur through radioactivities of the first radio module and can lead to an alleged loss ofsynchronism, not as is usual with known systems for the moment ofcommunication of the ESL radio module, but rather predictively forfuture radio activities in the common radio medium through an automaticplanning of these radio activities. This is also accompanied by asubstantially more efficient radio activity of the two radio modules.

Thus for example for a second communication protocol, which during atime slot cycle of 15 seconds provides 256 time slots of approx. 58.5milliseconds each, the future time period to be taken into account canhave a duration of 0.5-15 seconds. Preferably the future time period hashowever a duration of approx. 0.5-3, in particular 0.75-1.5 seconds. Thetime details given here are based on experiments of the applicant. Theyare dependent on the communication with a server (see further below),the storage demand or even the reaction time.

It should generally be kept in mind that a meaningful future time periodis a multiple of the time, for which individual “radio activities” ofboth radio systems use the radio medium. For the ESL radio moduletypical values are 2-54 seconds. For WLAN this may even be severalhundred milliseconds. A larger time period makes predictive planningmore complicated, but opens up more possibilities during coordinating.The ideal time period is thus a compromise between the complexity duringpredictive planning and the effectiveness during coordinating.

The time values mentioned above contribute to a good balance between astable ESL radio system, in which synchronism for the respective displaysigns can be reliably ascertained, and sufficient flexibility for takinginto account radio activities to be completed over time, this withoutcausing needlessly high expenditure in terms of processing/planning forthe future time period. Viewed long term, i.e. over the entire operatingperiod of the ESL radio system for example, this also leads to anenergy-optimised operating scenario.

According to a further aspect of the invention the radio base stationcomprises an electronic circuit, the USB connection mentioned and aprogrammable circuit component for executing a software, with the aid ofwhich said first control stage and/or said second control stage and/orsaid third control stage is realised. Realisation of the control stagesmay be effected by hardware components of the circuit (even e.g.exclusively). This may be done by using for example an ApplicationSpecific Integrated Circuit (ASIC). Equally a single chip processor or amicroprocessor with its typical peripheral building blocks(input/output, storage modules etc.) may be used, on which a software isprocessed, which provides the functionality of the respective controlstage through the use of software. This software-based solution may e.g.be, for the first control stage, a WiFi device driver for controllingthe first radio module which in this case is realised as a WiFi radiomodule and, for the ESL control stage, is an ESL device driver forcontrolling the ESL radio module, which is connected to the electroniccircuit via said USB connection.

The third control stage can be called/realised as a software-based radiocoordinator, because this software plans/coordinates, which radioactivities shall take place within which time ranges within the futuretime period. It may be configured as a component of the software of thedevice driver for the first or for the second radio module or may alsobe present and executed as a separate software component.

According to a further aspect of the invention the radio base stationmay comprise a storage tier for storing a first queue data structurerepresenting the future time sequence of radio activities of the firstradio module and a second queue data structure representing the futuretime sequence of radio activities of the ESL radio module. These queuedata structures are called “queue” in the technical jargon and theyserve to buffer data objects in chronological order before these arefurther processed by the respective device driver. Preferably the thirdcontrol stage is configured for reading (the data objects) of the secondqueue data structure and taking into account the time sequence of theradio activities defined there (represented by said data objects) forchanging the time sequence of the radio activities (represented by saiddata objects), which are stored in the first queue data structure forsaid future time period. This ensures priority of the ESL radioactivities over those of the first radio module.

According to a further aspect of the invention it may be of advantage ifthe third control stage is also configured for predictively changing thetime sequence defined by the second control stage for said time period,of radio activities of the ESL radio module on the basis of radioactivities of the first radio module defined for said time period by thefirst control stage. This permits taking the radio activities of bothradio modules into account in a balanced manner, when using the commonradio medium.

For the purpose of realising this functionality it has proven to beadvantageous if the third control stage is also configured for readingthe first queue data structure and taking into account the time sequenceof the radio activities as defined in there, for changing the timesequence stored in the second queue data structure of the radioactivities for said future time period. This also permits interventionwith the data objects—in particular their temporal occurrence duringradio-technical processing—of the second queue data structure. In thisrespect the third control stage is given the role of a software-basedco-existence coordinator.

In general it be stated that the sequence total stored in the firstqueue data structure of radio activities represents a first future totalcommunication period and the sequence total stored in the second queuedata structure of radio activities represents a second future totalcommunication period and that the first total communication period maybe different from the second total communication period, such as e.g. 3seconds for the first and 5 seconds for the second total communicationperiod. The actual duration of the respective future total communicationperiod results de facto from the respectively existing futurecommunication demand. Also, the respective maximum admissible totalcommunication period, in particular tailored to the communicationprotocol used, may be limited.

The future time period, for which the sequence of future radioactivities has to be changed, may then be limited to the shorter of thetwo total communication periods/i.e. dynamically adjusted to therespective situation. Also said future time period may deviate from thepreviously mentioned two total communication periods, and for examplerefer to an essentially constant duration of e.g. approx. 1 second.

Independently of whether the radio activities of the first radio moduleor also the radio activities of the second radio module are to bechanged, it has proven to be particularly advantageous to configure thethird control stage for changing the respective queue data structuresuch that, as regards the temporal occurrence and/or as regards thesuccession of such temporal occurrences, radio activities defined asmandatory are maintained in the time ranges/the succession of such timeranges provided therefore, and that other radio activities aredefined/planned in intermediate time ranges or subsequent time ranges.These measures ensure that those radio activities, which are necessaryto maintain the stability of the respective radio system, can indeedtake place in the correct temporal context. In addition it may beprovided with this configuration that ultimately those radio activitiesof the ESL radio module, which are mandatory for maintaining thesynchronism, are treated with the highest-most priority, in order tokeep the energy consumption of the display signs to a minimum and tooptimise their service life.

In order to make the previously discussed necessity of radio activitypossible, a code may be stored in the respective queue data structure,which allows the respective radio activity to be made uniquelyidentifiable. The third control stage may then be configured such thatit interprets the code and draws conclusions therefrom as to thenecessity of the respective radio activity. It has however proven to beparticularly advantageous if the third control stage is configured fortaking into account metadata, wherein the metadata is stored in therespective queue data structure and (directly) indicates the necessityof the temporal occurrence of the respective radio activity or the typeof the respective radio activity.

The metadata can categorise the respective radio activities in the queuedata structure, such as e.g.:

-   -   type of radio activity (e.g. synchronisation, data exchange,        status query, etc.),    -   temporal flexibility of the radio activity,    -   which provides information on the possibility of re-arranging        the respective queue data structure (e.g. re-arranging allowed,        re-arranging denied, because real-time transmission at the        originally defined point in time is required, i.e. changing the        temporal occurrence is denied) or    -   which allows to make a decision as to whether the temporal        context in relation to other radio activities must be maintained        or can be dissolved (e.g. chronological order and/or mutual        temporal distance must be maintained), or    -   which allows to make a decision as to whether the respective        radio activity may be divided up into different, in particular        non-contiguous time ranges (e.g. dividing-up allowed,        dividing-up denied),    -   time duration of the radio activity, which allows to define the        duration for the time range or the time ranges for the        respective radio activity (e.g. duration of radio activities        stated in absolute time units such as milliseconds, data        quantity rated with transmission speed, etc.),    -   priority of the radio activity for identifying the importance of        the respective radio activity in the context of the respective        communication protocol (e.g. indicated by the “high”, “medium”,        “low” indicators).

According to a further aspect of the invention the third control statemay be configured for making iterative changes such that initially theradio activities defined as mandatory are taken into account followed bythe other radio activities for said time period. When changing thesequence of radio activities therefore the radio activities defined forsaid future time duration are analysed first, and then those radioactivities are identified, which are mandatory and defined for theassociated time range within the future time period, and only then arethe other radio activities defined for time ranges within the viewedfuture time period, which are still free/unallocated. Two or more runsmay be necessary for this process of defining the radio activities. Thisin particular then, when radio activities defined as mandatory for boththe ESL radio module and for the first radio module are identified forone and the same time range or for at least overlapping time ranges. Inthis case a further change operation would be necessary in order to givepreference to the radio activities of the ESL communication module inorder to ensure the stability and efficiency of the ESL radio system.The radio activities of the first radio module identified as colliding,but rated as mandatory would then have to be defined in a further run inthe time ranges which have remained free, and the time ranges whichthereafter have still remained free would then be allocated to thoseradio activities which were identified as not mandatory. Here again adouble or even multiple run can take place, in which initially the ESLradio activities of the first radio module rated as not mandatory andfinally the radio activities of the first radio module rated as notmandatory, are defined in the future time period.

In order to ensure a sustainable optimal use of the common radio medium,it has proven to be particularly advantageous that the third controlstage is configured for a continuous or stepwise adjustment of thechange in time sequence defined by the respective control stage for saidfuture time period, of radio activities with regard to the progress oftime and/or newly added radio activities. This allows, for example,changing the sequence of radio activities for each newly added radioactivity, which corresponds to a (quasi) continuous adjustment of thechange. Equally, but preferably, a series of newly added radioactivities may also be taken as a reason for adjusting the change intime sequence of the radio activities for a future time period. Thiscorresponds to a blocked, stepwise adjustment of the change. As such 5,10 or even 15 newly added radio activities for example may be used as areason for adjusting the change in the time sequence of the radioactivities for a future time period.

Finally the future time period to be actually considered may not be aconstant, but a function of the radio activities contained therein or tobe taken into account. In this context the third control stage mayhowever also be configured to keep the actual duration of the timeperiod within predefined limits.

Preferably a system can be realised with the aid of the invention, whichcomprises (at least) one inventive radio base station and an ESL radiomodule connected to the USB connection. The system, which may e.g. beinstalled in a shop, may also comprise a number of electronic displaysigns, which are assigned to the ESL radio module in a radio-technicalmanner, e.g. by initial login (also called registration).

Furthermore a server (service) coupled to the radio base station may beprovided for providing and/or processing data relating to the radiocommunication with the first radio communication devices and/or theelectronic display signs. Coupling may for example be LAN-based orCloud-based.

This and further aspects of the invention are revealed in the figuresdiscussed below.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be discussed once more in detail with referenceto the attached figures by way of exemplary embodiments, to whichhowever the invention is not restricted. In the various figuresidentical components are marked with identical reference symbols.

The figures are schematically drawn, each depicting:

FIG. 1 an inventive system for WiFi and ESL communication;

FIG. 2 a first state diagram relating to the ESL communication;

FIG. 3 a second state diagram relating to the ESL communication;

FIG. 4 a third state diagram relating to the ESL communication;

FIG. 5 a first radio activities diagram;

FIG. 6 a second radio activities diagram.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 visualises an inventive system 1 installed in the premises of asupermarket, which provides a first radio network for WiFi radiocommunication in accordance with a first WiFi communication protocolwith different WiFi-capable radio communication devices, such as one ormore portable electronic barcode reading devices 11 which are part of anelectronic product management system of the supermarket, or e.g. alsomobile telephones or mobile computers of customers, in the followingcalled user devices 16 for short, which may for example gain access toonline-services via a WiFi guest access of the first radio network.

The system 1 also provides a second radio network in accordance with asecond, namely proprietary communication protocol with a number ofelectronic price display signs 2-10, in the following called ESL 2-10for short, which are also part of the electronic product managementsystem of the supermarket. Each ESL 2-10 comprises a display unit 100and is attached to shelf bases 12-14 of a shelf 15 according to theproducts (not shown) positioned on the shelf base, for which with theiraid price and/or product information is displayed for the information ofcustomers or supermarket personnel.

The two different communication protocols differ in their temporalbehaviour and also comprise different priorities.

These radio networks are realised in that the system 1 comprises a radiobase station 17, called station 17 for short, and a server 18, which areconnected with each other via a local wired network (LAN) 19. The server18 communicates via this LAN 19 with the station 17 using the TCP/IPprotocol, wherein raw data RD embedded in communication data KD can beexchanged with the respective devices 2-10, 11 and 16.

The station 17 comprises a first electronic circuit 20, a first radiomodule 21 for radio communication with the barcode reading devices 11and a USB connection 29, to which a second radio module 22 is connected,which is called an ESL radio module 22 for communication with the ESLs2-10.

The circuit 20 comprises a micro controller 24 with a memory 25, whichcomprises a non-volatile memory area (e.g. ROM—Read Only Memory—orE{circumflex over ( )}2PROM—Electrically Erasable Read Only Memory) anda volatile memory area (e.g. RAM—Random Access Memory), both of whichhowever are not depicted. Three control stages are realised with the aidof software modules, which are stored in the non-volatile memory areaand which are processed on the microcontroller 24; a first control stage26 which is the WiFi device driver for controlling the WiFi radiocommunication, a second control stage 27, which is the ESL device driverfor controlling the ESL radio communication and a third control stage 28for predictively changing the time sequence defined by the first controlstage 26 for a future time period, of WiFi radio activities of the firstradio module 21 on the basis of ESL radio activities defined by thesecond control stage 27 for said future time period, of the ESL radiomodule 22, the latter to be discussed in detail further below.

The first radio module 21 comprises a second programmable electroniccircuit 30, which processes a first firmware 31 of the first radiomodule 21. The first radio module 21 and the first electronic circuit 24are installed in the device housing (not shown) of the radio basestation 17 and electronically connected to each other. A first aerial 32connected to the second electronic circuit 30 is mechanically fastenedto the device housing. The aerial 32 may however also belocated/installed internally in the device housing.

The ESL radio module 22 comprises a third programmable electroniccircuit 33, which processes a second firmware 34 of the ESL radio module22. The ESL radio module 22 is located externally to the device housingof the radio base station 17 and comprises a third programmableelectronic circuit 33, which processes a second firmware 34 of the ESLradio module 22. The ESL radio module 22 is located outside the devicehousing of the radio base station 17 and comprises its own devicehousing (not shown). A second aerial 35 electronically connected to thethird electronic circuit 33 is mechanically fastened to the devicehousing of the ESL radio module 22. The ESL radio module 22 comprises aUSB plug 36, which connects the third circuit 33 to the USB connection29 via a USB cable 37.

The server 18 comprises a data storage tier 40, e.g. for storing adatabase for storing all information relating to the product managementsystem and/or the communication with individual subscribers of the radionetwork. A software which runs on a data processing stage 41 of theserver 18 realises the product management system.

In the communication between the ESLs 2-10 and the ESL radio module 22to which they are logically/radio-technically assigned by e.g. previousregistration, a proprietary time slot communicationprotocol/communication process is used, the principle of which isvisualised in FIGS. 2-4 and with the aid of which the mode offunctioning of the system 1 is illustrated.

The time t is plotted on the x-axis. States Z of the respectivecomponents considered in the discussion/signals of system 1 are plottedon the y-axis. The diagrams show the temporal course of the states.

In FIGS. 2-4 the uppermost state sequence shows the states of the ESLradio module 22 marked with ST. During a time slot cycle duration DC(e.g. 15 seconds) N time slots Z1 . . . ZN (e.g. 256) with identicaltime slot duration DS (e.g. approx. 58 milliseconds) are available.During the time slot cycle duration DC the ESL radio module 22alternates between a transmitting state T and an idle state R. Thetransmitting state T is always adopted at the beginning of a time slotZ1 . . . ZN and maintained for a synchronisation data signal durationDSD (or for a transmitting time duration DSD of the synchronisation datasignal SD) in order to send an applicable time slot symbol ZS1, ZS2, . .. ZSN with the respective synchronisation data signal SD. Therespectively applicable time slot cycle signal ZS1, ZS2, . . . ZSN usedis the serial number of the respective time slot Z1 . . . ZN in theorder of occurrence of the time slots Z1 . . . ZN.

FIG. 2 shows that the first ESL 2 is in the synchronous state. It wakesup at a first waking-up time TA1 from its extremely energy-saving sleepstate S and changes with a relatively short lead time DV prior to anexpected occurrence of a synchronisation data signal SD into itsready-to-receive active state E, receives the synchronisation datasignal SD during a receive time duration DE with the first time slotsymbol ZS1, ascertains by comparing the lowest-value byte B0 of itshardware address with the received time slot symbol ZS1 that the firsttime slot Z1 determined for the first ESL 2 is displayed (match of thebytes to be compared: B0 of the hardware address and first time slotsymbol ZS1), retains the parameters used for controlling the waking-upfor the waking-up in the subsequent time slot cycle for the purpose ofdefining the new waking-up time and changes back into the sleep state Swith a relatively short trailing time DN in order to, following expiryof the envisaged sleep state dwell time DR, wake up as planned at thenew second waking-up time TA2 with said lead time DV prior to therenewed beginning of the first time slot cycle Z1. The same appliesanalogously to the second ESL 3 as well as to all other ESLs 4-10insofar as they are like the first ESL 1 in the synchronous state. AllESLs 2-10 are configured to recognise a non-synchronous state and tore-synchronise, which is accompanied by a considerably increased energydemand in comparison to that in the sleep state.

With the aid of FIG. 3 individual addressing of ESLs 2-4 as well asindividual commissioning of these ESLs 2-4 is discussed with the aid ofsingle time slot demands. The drawing only shows the first time slot Z1embedded between two synchronisation data signals SD. Address data AD,command data CD and acknowledgement time data ZD are embedded by the ESLradio module 22 in the synchronisation data signal SD of the first timeslot Z1. The first ESL 2 is individually addressed with the aid ofaddress data AD (e.g. Hex B2:00:01), the second ESL 3 is addressed withthe aid of address data (e.g. Hex B2:00:02) and the third ESL 4 isaddressed with the aid of address data (e.g. Hex B2:00:03). With the aidof the command data CD a “PING” command is communicated to the first ESL2, a “PING” command is also communicated to the second ESL 3 and a“SWAPG2” command is communicated to the third ESL 4. These commands aresingle time slot commands, which are processed immediately after theirdecoding in the respective ESL 2-4 with a negligible amount of time.

With the aid of the two “PING” commands it is tested whether theaddressed ESL 2, 3 reports back with acknowledgement data ACD or whetherit exists or at all reacts and is synchronised. With the aid of the“SWAPG2” command a switch-over is initiated for the third ESL 4 from a(first) current memory page to a second memory page in order to e.g.change the image to be shown with the aid of its display. In additionthe synchronisation data signal SD is used to communicate anacknowledgement time, by indicating, for the first ESL 2 a first idletime period DR1, for the second ESL 3 a second idle time period DR2, andfor the third ESL 4 a third idle time period DR3. The reference pointfor the three idle time periods DR1-DR3 is always the end of the receivetime duration DE. Instead of individual idle time periods DR1-DRD3maximum time durations for replying may be set, which result from thesum of the respective idle time duration DR1-DR3 and the time period forissuing the acknowledgement data ACD. According to FIG. 3 all three ESLs2-4 recognise that they are synchronous because the first time slotsymbol Z1 indicates the time slot destined for it (lowest-value byte B0of the hardware address is Hex 00 for all three ESLs 2-4). The check ofthe address data AD indicates that each ESL 2-4 is individuallyaddressed (existence of the three remaining bytes B1-B3 of therespective hardware address in the address data AD), the commandsdestined for the respective ESL 2-4 are decoded and immediatelyexecuted, and, following expiry of the individual idle time periods DR1. . . DR3 at the end of the receive time duration DE, the individualacknowledgement data ACD is communicated to the ESL radio module 22,which during a station receive time duration SDE is ready to receive theacknowledgement data ACD. Processing of the single time slot commandsincluding the communication of the acknowledge data ACD is completed ina first part 42 of the time slot Z1, so that a second part 43 isavailable for other tasks such as the processing of multiple time slotcommands, which is discussed in more detail below.

FIG. 4 shows the processing of a multiple time slot command, where thefirst ESL 2, across three adjacent time slots Z1-Z3, receives total data(e.g. concerning an overall image or only a single image plane of theimage to be depicted) divided into three data packets DAT1-DAT3 from theESL radio module 22. The first ESL 2 recognises, with the aid of thesynchronisation data signal SD, its synchronous state and the fact thatit has been individually addressed (address data Hex B2:00:01) and itreceives and decodes a “DATA_INIT” command, with which it is told toreceive the three data packets DAT1-DAT3 in said time slots Z1-Z3, and,at the end of the receive duration DE enters into the sleep state S fora first waiting period during DW1, wherein the first waiting period DW1expires with the end of the first half of the time slot duration DS. Atthe beginning of the second part 43 of the first time slot Z1 the ESLradio module 22 enters into its transmitting state T and the first ESL 2enters into its ready-to-receive active state E, so that it receives thefirst data packet DAT1 during a data transmission period DT. Thereafterit acknowledges the successful receipt with the aid of partialacknowledgement data ACD1 during an acknowledgement time duration DA,during which the ESL radio module 22 is also in the receiving state E.The acknowledgement time duration DA ends prior to the end of the firsttime slot Z1. After expiry of the acknowledgement time duration DA thefirst ESL 2 dwells in the sleep state S for a second waiting period DW2,which extends until the end of the first part 42 of the second(subsequent) time slot Z2. At the beginning of the second part 43 of thesecond time slot Z2 the ESL radio module 22 enters into its transmissionstate T and the first ESL 2 enters into its ready-to-receive activestate E, so that it receives the second data packet DAT2 during a datatransmission period DT. The same applies to the third time slot Z3, atthe end of which data transmission is finished. Each successfullytransmitted data packet DAT1-DAT3 is acknowledged with the aid ofpartial acknowledgement data ACD1-ACD3.

The data transmissions to be performed by the two radio modules 21 and22 are communicated from the server 18 to the station 17 prior to theiractual arrival and stored there in the volatile storage area of thestorage tier 25 on the one hand in a first queue data structure 38 as asequence of future radio activities for the WiFi radio module 21 and, onthe other hand, in a second queue data structure 39 as a sequence offuture radio activities for the ESL radio module 22. Access to the firstqueue data structure 38 is effected via the first control stage 26, inorder to control the WiFi radio activity of the WiFi radio module 21corresponding to the stored entries in accordance with the WiFicommunication protocol used. Access to the second queue data structure39 is effected via the second control stage 27, in order to control theESL radio activity of the ESL radio module 22 corresponding to thestored entries in accordance with the discussed time slot communicationprotocol. The control states 26 and 27 operate synchronously, whereinthey use a common time basis of the electronic circuit 20. They alwaysread the description of the respective radio activity stored in therespective queue data structure 38/39 for the actual point in time andimplement this by controlling the associated radio module 21/22.

Moreover the station 17 comprises a third, separately configuredsoftware-based control stage 28, which also utilises the common timebasis and changes the sequences of WiFi radio activities stored in thefirst queue data structure 38 on the basis of the sequences of ESL radioactivities stored in the second queue data structure 39. The thirdcontrol stage 28 ignores the radio activity/activities present for thecurrent moment and only considers that sequence of radio activities,which follow next in terms of time and occur within a maximum futuretime period of approx. one second. Radio activities going beyond thistemporal horizon/possibly occurring at a later stage and which are, asthe case may be, defined in the respective queue data structure 38/39,are not taken into account until over time they are within said futuretime period.

The functional principles/designs of the third control stage 28 arediscussed below by way of example with the aid of FIGS. 5-6.

In the present case it may now be assumed according to a firstembodiment that channels with (at least partially) overlappingfrequencies are used for the radio activities of the two radio modules21 and 22, from which it follows that apart from receiving radioactivities (such as e.g. the receipt of acknowledgement data ACD orpartial acknowledgement data ACD1-ACD3) transmitting radio activities ofthe ESL radio module (in particular for sending the synchronisation datasignal SD) are also to be coordinated/to be taken into account duringpredictive planning.

In FIG. 5 the ESL radio activities F1(N) are depicted in the lower areaand the WiFi radio activities F2(M) are depicted in the central areaacross the time axis t, wherein the bracketed letters N and Mrepresenting a positive integer each indicate the serial number of therespective radio activity F1(1)−F1(5)/F2(1)−F2(4). The radio activityF2(1) present at the point in time t=0 (presence) is being presentlyimplemented by the WiFi radio module 22 and therefore is no longer takeninto account by the third control stage 28 because it had already beentaken into account at an earlier point in time. The third control stage28 only considers the future ESL radio activities F1(1)-F1(7) and thefuture WiFi radio activities F2(1)-F2(4), which occur within the futuretime period TD and are stored in the respective queue data structure38/39. Entries in the respective queue data structure 38/39 going beyondthis temporal horizon are not taken into account until, as timeprogresses, i.e. when the time stamp t=0 (presence) moves to the right,these other entries enter into the temporal horizon (right-hand end) ofthe future time period TD.

In the present case the radio activities F1(1) to F1(5) refer to theemission of the synchronisation data signal SD comprising the respectivetime slot symbol ZS1-ZS6, which is essential for maintaining thesynchronism in the ESL radio system. They essentially occupy time rangesof the same length. The radio activities F1(6)/F1(7) refer to acommunication in the ESL radio system as specified in the description ofFIG. 3 or 4. They can occupy time ranges of different duration dependingon the actual data content/data volume.

In the present case the third control stage 28 knows the temporalbehaviour of the ESL communication protocol and prioritises the ESLradio activities F1(1)-F1(7) over the WiFi radio activities F2(1)-F2(4).Accordingly it intervenes in the time sequence of the of WiFi radioactivities F2(1)-F2(4) and changes these as shown in the uppermostsection of FIG. 5, where the sequence of WiFi radio activities F2(M)′modified as regards its temporal occurrence is depicted for the futuretime period TD, so that the ESL radio activities F1(1)-F1(7) can beimplemented without interruption. In this respect the WiFi activity:

-   -   F2(2), which would begin in the time range of the ESL radio        activity F1(1), is moved slightly into the future (see F2(2)′),        so that it starts after the ESL radio activity F1(1),    -   F2(3), which would end in the time range of the ESL radio        activity F1(2), is brought forward slightly, (see F2(3)′), so        that it ends before the ESL radio activity F1(2), wherein the        time range remaining after the WiFi radio activity F2(2)′ is        optimally utilised prior to the occurrence of the ESL radio        activity F1(2),    -   F2(4), which would overlap with the ESL radio activities F1(6)        and F1(3), is divided across later time ranges between the ESL        radio activities F1(3), F1(7), F1(4) and F1(5) (see three radio        activities F2(4)′).

According to a further development of the previously discussed design ofstation 17 metadata M1-M5 is used for the respective radio activitiesF1(N) and F2(M), wherein reference should be made to FIG. 6. Furthermorethe third control stage 28 is configured for changing the time sequenceof the WiFi radio activities F2(M) and the ESL radio activities F1(N)with regard to metadata M1-M5. The change in the time sequence of theESL radio activities F1(N) is visualised in diagram section F1(N)′ andthe change in the time sequence of the WiFi radio activities F2(M) isvisualised in diagram section F2(M)′.

Furthermore it may be assumed that maintaining the synchronism of theESL radio system is given the highest priority. First metadata M1 thusdefines the highest priority for the radio activities F1(1)-F1(5), aswell as a ban to change their temporal distance from each other or tolet them occur in a different order from that in the sequence of radioactivities F1(N). The third control stage 28 thus keeps them in theiroriginal time ranges, as can be seen when comparing diagram F1(N) withdiagram F1(N)′.

For the two WiFi radio activities F2(2) and F2(3) second metadatadefines the lowest priority and the fact that their temporal occurrenceas well as the temporal distance from adjacent radio activities isnon-critical, namely variable. The third control state 28 thus movesthem between the two ESL radio activities F1(1)′ and F1(2)′.

In addition third metadata M3 defines that the radio activity F2(4) hassecond highest priority, but that its temporal context is non-critical,which means that it can be divided up across different time ranges.Fourth metadata M4, which characterises the ESL radio activity F1(6),defines a lower priority than for the WiFi radio activity F2(4) andpermits to perform the ESL radio activity F1(6) in another butcontiguous time range. In addition fifth metadata M5 defines that theESL radio activity F1(7) also is to be performed with the highestpriority and in an immovable and undividable manner. Building on thisinformation the third control stage 28 divides the WiFi radio activityF2(4) up in such a way that a longer part occurs prior to the ESL radioactivity F1(3)′ and shorter part occurs after it, but prior to the ESLradio activity F1(7)′, for which no temporal change is planned relativeto radio activity F1(7) (see two radio activities F2(4)′). Furthermorethe ESL radio activity F1(7) is left in its originally defined timerange (see F1(7)′). Finally the ESL radio activity F1(6) is moved intothe next available time range as regards its required duration, namelyinto the time range between the ESL radio activities F1(4)′ and F1(5)′(see F1(6)′ in there).

The result of the respective change is depicted in the diagram sectionsF1(N)′ and F2(M)′, where it can be seen that no temporal overlapping ofradio activities exists when comparing the two diagram sections F1(N)′and F2(M)′.

Furthermore it may now be assumed according to a second exemplaryembodiment that channels without overlapping frequencies are used forthe radio activities of the two radio modules 21 and 22. The advantageof this is that the focus during predictive planning/coordinating nowlies on the signals which are emitted by the ESLs 2-10. These are,although not exhaustively listed, e.g. the acknowledgement dataADC/partial acknowledgement data ACD1-ACD3, for which it is predictivelyensured according to the previously discussed function principles thatno interferences can occur in the common radio medium.

In conclusion it is to be pointed out once more that the figuresdescribed in detail above are exemplary embodiments, which may bemodified in the most varied ways by the expert without leaving the scopeof the invention. For completeness sake it is to be noted that use ofthe indefinite article “a” does not exclude that there may be more thanone incidence of the respective features.

1. A radio base station (17) comprising a first radio module (21, 23)for radio communication with first radio communication devices (11, 16),and a connection (29) for connecting an ESL radio module (22) for radiocommunication with electronic display signs (2-10), wherein the radiobase station (17) comprises: a first, in particular software-based,control stage (26) for controlling the radio communication of the firstradio module (21, 23) in accordance with a first communication protocol,and a second, in particular software-based, control stage (27) forcontrolling the radio communication of the ESL radio module (22)connectable to the connection (29) in accordance with a secondcommunication protocol, and a, in particular software-based, thirdcontrol stage (28) for predictively changing a time sequence defined fora future time period (TD) of radio activities (F1(N)) of the first radiomodule (21) on the basis of radio activities (F2(M)) of the ESL radiomodule (22), which are defined for said future time period (TD).
 2. Theradio base station (17) according to claim 1, comprising a storage tier(25) for storing a first queue data structure (38) representing thefuture time sequence of radio activities of the first radio module (21)and a second queue data structure (39) representing the future timesequence of radio activities of the ESL radio module (22), wherein thethird control stage (28) is configured for reading the second queue datastructure (39) and, in consideration of the time sequence of radioactivities (F2(M)) defined therein, for changing the time sequencestored in the first queue data structure (38) of the radio activities(F1(N)) for said future time period (TD).
 3. The radio base station (17)according to claim 2, wherein the third control stage (28) is alsoconfigured for predictively changing said time sequence (TD) of radioactivities (F2(M)) of the ESL radio module (22), as defined by thesecond control stage (27), on the basis of radio activities (F1(N)) ofthe first radio module (21) which are defined by the first control stage(26) for said time period (TD).
 4. The radio base station (17) accordingto claim 3, wherein the third control stage (28) is configured forreading the first queue data structure (38) and, in consideration of thetime sequence of radio activities (F1(N)) defined therein, for changingthe time sequence stored in the second queue data structure (39) of theradio activities (F2(M)) for said future time period (TD).
 5. The radiobase station (17) according to claim 1, wherein the third control stage(28) is configured for changing the respective queue data structure (38,39) in such a way that as regards the temporal occurrence and/or asregards the succession of temporal occurrences, the radio activities(F1(N), (F2(M)) defined as mandatory are maintained in the time rangesprovided for them or in the provided succession of such time ranges andin that other radio activities (F1(N), (F2(M)) are defined inintermediate time ranges or subsequent time ranges.
 6. The radio basestation (17) according to claim 5, wherein the third control stage (28)is configured for taking metadata (M1-M5) into account, wherein themetadata (M1-M5) is stored in the respective queue data structure (38,39) and indicates the necessity of the temporal occurrence of therespective radio activity (F1(N), (F2(M)) or the type of the respectiveradio activity (F1(N), (F2(M)).
 7. The radio base station (17) accordingto claim 5, wherein the third control stage (28) is configured formaking iterative changes such that initially the radio activities(F1(N), (F2(M)) defined as mandatory and only thereafter the other radioactivities (F1(N), (F2(M)) for said time period (TD) are taken intoaccount.
 8. The radio base station (17) according to claim 1, whereinthe third control stage (28) is configured for continuous or stepwiseadjustment of the change in the temporal sequence of radio activities(F1(N), (F2(M)) to be initiated by the respective control stage (26, 27)for said future time period (TD), as time (t) passes and new radioactivities (F1(N), (F2(M)) are added.
 9. The radio base station (17)according to claim 1, comprising an electronic circuit (20) having saidconnection (29) and a programmable circuit component (24) for processinga software with the aid of which said first control stage (26) and/orsaid second control stage (27) and/or said third control stage (28) isrealised.
 10. A system (1) comprising a radio base station (17)according to claim 1 and an ESL radio module (22) connected to theconnection (29).
 11. The system (1) according to claim 10 comprising aserver (18) coupled to the radio base station (17) for providing and/orprocessing data (RD) concerning the radio communication with the firstradio communication devices (11, 16) and/or the electronic display signs(2-10).
 12. A method for controlling a radio communication of a radiobase station (17), wherein the radio base station (17) comprises a firstradio module (21) for radio communication with first radio communicationdevices (11, 16) and a connection (29) for connecting an ESL radiomodule (22) for radio communication with electronic display signs(2-10), wherein according to the method a first, in particularsoftware-based, control stage (26) controls the communication of thefirst radio module (21) according to a first communication protocol, anda second, in particular software-based, control stage (27) controls thecommunication of an ESL radio module (22) connected to the connection(29) according to a second communication protocol, and a third, inparticular software-based, control stage (28) predictively changes atime sequence of radio activities (F1(N)) of the first radio module (21)as defined for a future time period (TD) on the basis of radioactivities (F2(M) of the ESL radio module (22), as defined for saidfuture time period (TD).
 13. The method according to claim 12, whereinthe third control stage (28) also predictively changes the time sequenceof radio activities (F1(N)) of the ESL radio module (22), as defined bythe second control stage (27) for said time period (TD), on the basis ofradio activities (F2(M)) of the first radio module (21), as defined bythe first control stage (26) for said time period (TD).
 14. The methodaccording to claim 12, wherein the third control stage (28) performs therespective change in such a way that as regards the temporal occurrenceand/or as regards the succession of the temporal occurrences radioactivities (F1(N), (F2(M)) defined as mandatory are maintained in thetime ranges provided therefore or in the provided succession of suchtime ranges and that other radio activities (F1(N), (F1(N)) are definedin intermediate or subsequent time ranges within the time period (TD).15. The method according to claim 14, wherein the change effected by thethird control stage (28) is performed iteratively in such a way thatinitially the radio activities (F1(N)), (F2(M)) defined as mandatory andonly thereafter the other radio activities (F1(N), (F2(M)) for said timeperiod (TD) are taken into account.